1. Field of the Invention
The invention relates to a recloseable lid for use with a drinking cup. In one aspect, the invention relates to a recloseable lid with a removable plug assembly which is operable between an open position, where a user can consume the contents of the cup, and a closed position, where the contents of the cup are inhibited from spilling. In another aspect, the recloseable lid assembly is suitable for disposable use, especially in the fast-food or take-out food market.
2. Description of the Related Art
Disposable cups with lids that inhibit spilling while allowing consumption of the liquid contained therein are well known in the industry. One type of lid incorporates a series of narrowly spaced baffled slots through which the liquid can be consumed. The narrow spacing of the slots and the baffles minimizes but does not eliminate spillage while allowing the liquid to be consumed. Another type of lid incorporates a flap that can be torn back from the rim of the cup toward the center of the lid and is secured in an open position to provide a drinking aperture. The lid can be re-closed by reattaching the flap to the rim of the cup. However, while these cups have the benefit of being disposable and relatively spill-proof during consumption, these lids are not resealable and liquid can be spilled when the consumer is not drinking from the cup.
There are non-disposable, recloseable lids that can be used with non-disposable cups that can inhibit spilling such as during the normal operation of a motor vehicle. One such recloseable lid comprises a well that is sized to be received within the opening of the cup. Multiple O-rings are disposed about a peripheral wall of the well and contact the cup to form a fluid-seal therebetween. A bottom wall of the well has a through opening permitting the passage of fluids from the cup. A rotatable cover is positioned within the well against the bottom wall and includes a projection and a through opening. When the through openings of the well and the cover align, a consumer can drink the contents from the cup. When the projection is received within the well through opening, the cup is closed.
The recloseable well structure is advantageous in that the lid can be closed to inhibit spilling and to the extent fluid is spilled it can be retained in the well. The lid is disadvantageous in that the well structure extends into the cup, which reduces the cup liquid capacity. The lid is also not suitable for use as a disposable lid in the fast-food or take-out food market because of its apparent manufacturing complexity, which requires the use of injection molding techniques.
Another group of non-disposable lids are injection molded lids with a drink opening in combination with an attached plug or cap for closing the drink opening. In some cases, the plug is separately molded and mechanically fixed to the lid by a cooperating projection molded into the lid. In other cases, the plug has a rivet-like projection that extends through an opening molded in the lid.
The nature of the injection molding process makes these lids unsuitable for disposable use because of the relatively high cost. Disposable lids are typically fabricated from thermoforming due to lower fabrication costs and higher production rates. Injection molded lids generally use a much greater amount of material and have a greater thickness than thermoformed lids. The additional material and thickness is well suited for non-disposable lids, but adds additional and unnecessary cost for a disposable lid where only a one-time use is anticipated.
However, the injection molding process is more suitable for making lids with complex shapes and strong connection/support structures, without a lot of material waste. The injection mold defines a three-dimensional cavity that is filled with molten plastic to form the lid. The mold can be made to accommodate almost any desired three-dimensional shape. However, the thermoforming process uses an effectively two-dimensional sheet of material that is pressed around a form. For example, a recloseable lid having an integral closure device extending from the lid upper surface can be easily formed by injection molding. However, such a lid cannot be formed with the thermoforming process, unless the integral closure is formed by tearing-away a portion of the lid upper surface, because both the lid and closure device must be made from the same portion of the sheet.
The distinction between injection molding and thermoforming can be thought of as the injection molding process can form pieces having varying thickness whereas the thermoforming process can only make parts having a thickness equal to, or due to stretching, less than, the thickness of the sheet material. Therefore, while the injection molding process can have increased thickness portions, such as webs, gussets, and the like, no such increased thickness portion can be made with the thermoforming process.
The ability of the injection mold to be crafted to handle complex designs is disadvantageous when it comes to production rates. The mold must be closed, filled with molten plastic, which then must be cooled sufficiently to retain its shape prior to the opening of the mold. In contrast, the thermoforming process uses a web of plastic that is heated to or beyond its glass state, which permits the web to be shaped but does not require a long cooling time as does the injection mold system. Thus, the thermoformed web is shaped and advanced to the next production step much faster than with the injection mold. The end result is that the thermoforming process has much higher production rates.
There is a desire for a recloseable lid that is easy and inexpensive to manufacture, preferably by using the thermoforming process, while still being able to maintain a seal after multiple cycles between the open and closed positions. Preferably, the recloseable lid would have a removable closure device and be suitable for disposable use in the fast-food or take-out food market. Previously, only injection molded lids could obtain this functionality. However, they were too expensive for high volume disposable use.